Apparatus for routing signals

ABSTRACT

An apparatus for routing signals to and from at least one circuit component that has a plurality of input/output leads includes a support structure having a first side and a second side. The first side is adapted to have the input/output leads of the circuit component attached thereto. A signal routing strip having a first end and a second end is also included. The first end of the routing strip is configured and adapted to be electrically connected to the input/output leads of the circuit component for transmitting signals to and from the circuit component.

BACKGROUND

The present invention generally relates to apparatus for routing signalsto and from circuit components, and more particularly to apparatus forreducing signal routing complexity and congestion, and increasing signalrouting flexibility.

The use of various integrated chips (ICs) having leads or contacts whichprotrude from the bottom or the sides of the packages and adapted to bepositioned on a printed circuit board (PCB) is commonly known.Typically, signals to and from components on the PCB are transmittedthrough signal paths formed in the PCB. These paths are generallyelectrically conductive traces which have a relatively fine width andimbedded in the multiple layers of the PCB to accommodate numeroussignals.

This known method of routing signals may be adequate for purposes ofrouting signals between a relatively small number of circuit components.However, it is not suitable when a large number of components, and acorrespondingly large number of signal paths between them, are required.The increase in the number of circuit components on the PCBsignificantly increases the complexity of the signal paths on the PCB,resulting in higher manufacturing costs. Expanding the size of the PCBto accommodate the increased number of circuit components could lead tostress fracturing of the delicate signal traces. Also, the known methodof signal routing is specific to a particular circuit componentconfiguration. Consequently, a PCB configured for one purpose generallywould not be suitable for different applications.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a simplified perspective view of a signal routing apparatus inaccordance with one embodiment of the present invention;

FIG. 2 is a perspective view of a routing strip shown in FIG. 1;

FIG. 2A is an enlarged side view of encircled section 2A of the routingstrip of FIG. 2;

FIG. 3 is a perspective view of another embodiment of a signal routingapparatus according to the present invention;

FIG. 4 is a perspective view of an integrated circuit (IC) in accordancewith the invention;

FIG. 4A is an enlarged view of a section of FIG. 4, illustrating theconnection between a die and a package of the IC;

FIG. 4B is an enlarged view of section 4B of FIG. 4, illustrating analternative method of making the connection between the die and thepackage.

FIG. 5 is a simplified side view showing the integrated circuit (IC) ofFIG. 4 attached to a printed circuit board and a routing strip; and,

FIG. 6 is a perspective view illustrating the manner in which a circuitcomponent is attached to the IC of FIG. 4.

DETAILED DESCRIPTION

Broadly stated, the present invention is directed to an apparatus forrouting signals to and from at least one circuit component that has aplurality of input/output leads. The apparatus includes a supportstructure having a first side and a second side. The first side isadapted to have the input/output leads of the circuit component attachedthereto. A signal routing strip having a first end and a second end isalso included. The first end of the routing strip is configured andadapted to be electrically connected to the input/output leads of thecircuit component for transmitting signals to and from the circuitcomponent.

The present device for routing signals to and from a plurality ofinput/output leads on a circuit component includes a strip having afirst side and a second side, and a first end and a second end. Aplurality of electrically conductive traces are imbedded in the stripbetween the first side and the second side. A plurality of electricalterminals extend from the conductive traces and protrude from the stripat the first end and the second end on at least the first side. Theterminals at the first end of the strip are configured and adapted to beconnected to the input/output leads on a first circuit component toenable signals to be transmitted to and from the first circuit componentfrom and to the terminals at the second end of the strip.

The present invention also relates to an integrated circuit deviceincluding a die for performing the functions of the integrated circuitdevice. The die has a plurality of input/output terminals. Also includedis a package which is configured and adapted to receive the die, and hasa top surface and a bottom surface. A plurality of external connectionleads are formed on the top surface and the bottom surface of thepackage, and connected to the input/output terminals of the die.

The external connection leads on the top surface are configured andadapted to be attached to corresponding input and output leads of acircuit component placed over the top surface of the package, so thatthe circuit component can be stacked directly on the top of theintegrated circuit device.

Turning now to FIG. 1, the signal routing apparatus of one embodiment ofthe present invention is indicated generally at 10 and includes asupport structure 12, preferably a printed circuit board (PCB), aplurality of circuit components 14 (two shown), and at least one routingstrip 16. The support structure 12 is constructed from known materialused for fabricating PCBs, such as fiberglass, for example, and includesa plurality of electrical and/or mechanical interfaces or land patterns18 (two shown). Each land pattern 18 is made of a plurality ofelectrically conductive holes or vias 20 which extend partially orcompletely through the support structure 12. The circuit components 14,such as integrated circuits (ICs), are adapted to be positioned over theland patterns 18 So that the input/output leads of the circuitcomponents (shown in FIG. 2 as 44) make electrical contact with the vias20. Accordingly, the vias 20 are arranged to match at least the patternof the electrical input/output leads 44 of a corresponding circuitcomponent 14. Preferably, each land pattern 18 includes a sufficientnumber of vias 20 to accommodate the different input and outputconfigurations patterns of various circuit components 14.

The routing strips 16 are adapted to transmit signals to and from thecircuit components 14 on the support structure 12. They transmit variousdata signals, as well as power to the circuit components 14, ifrequired. The routing strips 16 may also have signal lines for providingground for the circuit components 14. At least two end portions 22 areprovided on each of the routing strips 16, with each end portion havinga plurality of electrical terminals 24. These terminals 24 are adaptedto be connected to the land patterns 18 on the opposite side of thesupport structure 12 from the circuit components 14. In this manner, theterminals 24 electrically connect to the circuit components 14 throughthe vias 20, and signals to and from the circuit components aretransmitted by the routing strips 16. Accordingly, the terminals 24 atone end portion 22 are arranged to correspond to the input/output leadconfiguration on the corresponding circuit component 14. The terminalsat the other end portion 22 are arranged to correspond to theinput/output lead configuration of its corresponding circuit component.In this manner, signals between the circuit components 14 at the two endportions 22 are transmitted by the routing strip 16. The preferredmanner of connecting the terminals 24 of the routing strip 16 to thevias 20 is to attach solder balls to the terminals, align the terminalsto the corresponding vias and heat in oven until the terminals and thevias are soldered together.

Turning now to FIG. 2, the routing strip 16 is shown with the two endportions 22 having the plurality of terminals 24 in a pattern 26. Itshould be noted that the routing strips 16 may have more than two endportions 22 to carry signals between increased number of circuitcomponents 14. In an embodiment shown in FIG. 2A, the routing strip 16includes a top insulating/shield layer 28, a first signal trace layer30, a power plane 32, a second signal trace layer 34, a ground plane 36and a bottom insulating/shield layer 38. The top and the bottominsulating/shield layers 28, 38 insulate the routing strips 16 when theyare attached directly to the support structure 12 on which the circuitcomponents 14 are provided, and/or acts as a shield when high frequencysignals are being transmitted by the routing strips. The first and thesecond signal trace layers 30, 34 have electrically conductive wires ortraces 31 imbedded therein for carrying signals to and from the circuitcomponents 14. These traces begin and end at the terminals 24 on the endportions 22 of the routing strip 16. Power, if required, is supplied tothe circuit components 14 by electrically conductive traces or wires 33embedded in the power plane 32. The ground plane 36 provides anelectrical path in the form of a wire or trace 35 through which thecircuit components 14 on the support structure 12 are grounded.

It should be understood that the routing strip 16 described abovedepicts only one embodiment, and that it can have alternativearrangements. For example, the routing strip 16 may or may not includethe power plane 32 or the ground plane 36, depending on the type ofcircuit components 14 to which the routing strip 16 is designed to beconnected. Also, depending on the number of signals that the routingstrip 16 is designed to carry, it may have one or more signal tracelayers 30. Further, the routing strip 16 may be constructed from a rigidmaterial such as fiberglass, for example, or from a flexible plasticmaterial.

In accordance with another embodiment of the present invention, andreferring still to FIG. 2, the routing strip 16 is provided with theterminals 24 on a bottom side 40 of the routing strip, in addition tothose on a top side 42. The terminals 24 on the bottom side 40 allow thecircuit components 14 to be attached directly to the routing strip 16itself, in addition to the support structure 12, thereby furtherreducing complexity and congestion on the support structure 12. As withthe terminals 24 on the top side 42 of the routing strip 16, the bottomside terminals 24 are arranged in a pattern to correspond at least tothe input/output leads 44 of the corresponding circuit component 14.

As a variation of this embodiment, it is contemplated that all thecircuit components 14 be attached directly to the routing strips 16,thereby eliminating the necessity of the support structure 12, such as aPCB, altogether. The routing strips 16 can then be attached to theplastic, metal or other surfaces of the intended product housing thecircuit components 14.

Turning now to FIG. 3, and in accordance with another aspect of thepresent invention, the routing strip 16 is attached to the supportstructure 12 on the same side as the circuit components 14. In thisembodiment, the routing strip 16 is attached to the top surface 42 ofthe support structure 12 and the input/output leads of the circuitcomponents 14 are attached to the terminals 24 of the routing strip.This arrangement eliminates the necessity of creating vias 20 (shown inFIG. 1) on the support structure 12, which results in further reductionin manufacturing costs.

Referring to FIGS. 4 and 4A-4B, one embodiment of an integrated circuit(IC) 46 in accordance with the invention includes input/output leads 48formed both on its top surface 50 and a bottom surface 52. As inconventional ICs, the input/output leads 48 on the bottom surface 52 ofthe present IC 46 transmit signals to and from a die 54, the portion ofthe IC that performs the designed functions. In addition, the IC 46 ofthe present invention is adapted to also transmit signals to and fromthe die 54 through its input/output leads 48 on the top surface 50.

More specifically, the die 54 is seated in a depression or well 56 (bestshown in FIGS. 4A and 4B) of a package 55. The package 55 houses the die54 and also provides the surfaces 50, 52 from which the input/outputleads 48 are allowed to protrude. In accordance with one embodiment ofthe invention as shown in FIG. 4A, the die 54 is provided with aplurality of input/output terminals 57 on its bottom surface that facesthe floor of the well 56. The input/output terminals 57 may be solderballs which when heated bond to the package 55 on the floor of the well56. The input/output terminals 57 are arranged such that they makeelectrical connections with the ends of electrical conductors 58imbedded in the package 55. Each of the electrical conductors 58 haveone end which is exposed on the floor of the well 56 and the other endconnected to the input/output leads 48 on the top 50 or the bottom 52surfaces of the package 55. This arrangement allows the input/outputterminal 57 of the die 54 to be electrically connected to theinput/output lead 48 on the top 50 and the bottom 52 surfaces of thepackage 55 when the die is bonded to the floor of the well 56.

FIG. 4B shows another embodiment of the invention in which the die 54 isadhered to floor of the well 56 in the package 55, but does not have theinput/output terminals 57 provided on its bottom surface. Rather, theyare provided on the top surface 60 of the die 54. In the preferredembodiment, the input/output terminals 57 are electrically conductivepads disposed along the periphery of the die 54. However, otherconfigurations and manners of forming the terminals 57 are contemplatedas dictated by design choice. The input/output terminals 57 areconnected to the corresponding input/output leads 48 on the top 50 andthe bottom 52 surfaces of the package 55 via connection points 62 whichare provided along the periphery 64 of the well 56. The connectionpoints 62 are electrically connected to the input/output terminals 57 bywires 66, and to the input/output leads 48 on the top 50 and the bottom52 surfaces of the package 55 through conductors 58 embedded in thepackage 55, thereby completing the signal paths from the die 54 to theinput/output leads 48 on the package.

The IC 46 of the present invention is particularly adapted to be used inconjunction with the above-described routing strip 16, as shown in FIG.5. In FIG. 5, one end of the routing strip 16 is shown attached to theinput/output leads 48 on the top surface 50 of the IC 46, and the otherend attached to the support structure 12, preferrably a PCB. Theinput/output leads 48 on the bottom surface 52 of the IC 46 are attachedto the support structure 12. This arrangement increases the signalrouting flexibility to and from the IC 46. For example, high frequency,path critical (length, impedance, etc.) signals might be routed throughthose connections between the support structure 12 and the IC 46, whileless path critical signals might be routed through the routing strip 16.

The input/output leads 48 on the top surface 50 of the package 55 alsoallow the circuit component 14 to be mounted directly onto the IC 46. Anembodiment of this feature is illustrated in FIG. 6, which shows the IC46 having input/output leads 48 formed on the top surface 50 of thepackage 55 and on the bottom surface 52. The connections between theinput/output leads 48 and the die 54 are made in accordance with thedescriptions given above. The input/output leads 48 on the top surface50 form a land pattern 68 (i.e., a plurality of electrical interfaces),to allow the circuit component 14 to be attached directly onto the topsurface 50 of the IC 46. The circuit component 14 shown in the FIG. 6 isa conventional IC having the input/output leads 44 on its bottom surfacecorresponding to the input/output leads 48 of the land pattern 68. Theinput/output leads 44 of the circuit component 14 may be solder balls,for example, when heated and then cooled, are adapted to attachthemselves to their respective input/output leads 48 of the IC 46.

The input/output leads 48 on the bottom of the IC 46 are adapted to beconnected to a corresponding land pattern 18 on the support structure 12such as a PCB (best shown in FIG. 1). Alternatively, the IC 46, with orwithout the circuit component 14 attached, can be mounted on another IC46. In this arrangement, the input/output leads 48 on the bottom 50 ofthe first or top IC 46 would be arranged to make electrical connectionwith their corresponding input/output leads 48 formed on the top surface52 of the second or bottom IC 46. The second or bottom IC 46 may eitherbe attached to the support structure 12 or to the top surface 50 of yetanother or third IC 46, thereby further reducing congestion on thesupport structure 12 and increasing signal routing flexibility.

From the foregoing description, it can be seen that the variousembodiments of the present invention help reduce the complexity andcongestion on the signal carrying support structure by carrying signalson separate routing strips and/or stacking ICs directly on top of eachother. These arrangements contribute to prevention of stress fracturingof signal traces as the support structure becomes larger. The routingstrip also allows the support structure to be standardized by providingthe same land patterns on all the support structures and merely changingthe circuit components and the routing strips for differentapplications. The routing strip also enables ICs to have input/outputterminals on the top side of the package, thereby further increasingsignal routing flexibility.

While various embodiments of the present invention have been shown anddescribed, it should be understood that other modifications,substitutions and alternatives are apparent to one of ordinary skill inthe art. Such modifications, substitutions and alternatives can be madewithout departing from the spirit and scope of the invention, whichshould be determined from the appended claims.

What is claimed is:
 1. Apparatus for routing signals betweeninput/output leads of at least two circuit components on a circuitboard, said apparatus comprising: a strip having a first side and asecond side, and a first end and a second end; a plurality ofelectrically conductive traces imbedded in said strip between said firstside and said second side; and, a plurality of electrical terminalsextending from said conductive traces and protruding from said strip atsaid first end and said second end on at least said first side, whereinsaid terminals at said first end of said strip are configured andadapted to be connected to the plurality of input/output leads on afirst circuit component to route signals to and from the first circuitcomponent from and to said terminals at said second end of said stripand wherein said terminals at said second end on said first side of saidstrip are configured and adapted to be attached to the input/outputleads of a second circuit component on the circuit board.
 2. Theapparatus as defined in claim 1 wherein said terminals are arrangedsubstantially in a matrix pattern including a plurality of saidterminals along both rows and columns of said matrix.
 3. The apparatusas defined in claim 1 wherein said strip is substantially flexible. 4.Apparatus for routing signals between at least two circuit componentshaving a plurality of input/output leads, said apparatus comprising: asupport structure having a first side and a second side, said first sidebeing adapted to have the input/output leads of a first circuitcomponent attached thereto; and, a signal routing strip having a firstend and a second end, said first end being configured and adapted to beelectrically connected to the input/output leads of the first circuitcomponent for transmitting signals to and from the first circuitcomponent wherein said second end of said routing strip is attached to asecond circuit component on said support structure so that said signalscan be transmitted between the second circuit component and the firstcircuit component.
 5. The apparatus as defined in claim 4 furtherincluding a plurality of conductive patterns formed on said supportstructure and extending from said first side to said second side,wherein the input/output leads of a first circuit component are adaptedto be connected to a corresponding conductive pattern at said first sideof said support structure.
 6. The apparatus as defined in claim 5wherein said signal routing strip includes a first side and a secondside and a plurality of electrical terminals formed on at least saidfirst side at said first end and said second end, and said terminals onsaid first end of said first side are adapted to be connected to saidconductive pattern that corresponds to the input/output leads of thefirst circuit component at said second side of said support structure.7. The apparatus as defined in claim 6 wherein a plurality of electricalterminals are provided on said second side of said signal routing stripat said first end and said second end, said terminals being configuredand adapted to have at least one circuit component attached thereto atat least one of said first end and said second end.
 8. The apparatus asdefined in claim 6 wherein said electrical terminals at said second endof said signal routing strip are attached to said support structure sothat signals can be transmitted between said support structure and thefirst circuit component.
 9. The apparatus as defined in claim 8 whereinsaid electrical terminals at said second end of said signal outing stripare configured and adapted to be attached to the input/output leads of asecond circuit component which is attached to said first side of saidsupport structure through a conductive pattern corresponding to theinput/output leads of the second circuit component.
 10. The apparatus asdefined in claim 4 wherein said second end of said routing strip isattached to said first side of said support structure so that saidsignals can be transmitted between said support structure and the firstcircuit component.
 11. The apparatus as defined in claim 4 wherein saidsecond end of said routing strip is attached to said second circuitcomponent on said first side of said support structure so that saidsignals can be transmitted between said second circuit component and thefirst circuit component.
 12. The apparatus as defined in claim 4 whereinsaid first end of said routing strip is adapted to be electricallyconnected to the input/output leads on a top of the first circuitcomponent, and the input/output leads on a bottom of the first circuitcomponent is adapted to be attached said support structure.
 13. Theapparatus as defined in claim 4 wherein said first end of said routingstrip is disposed between the input/output leads on a bottom of thefirst circuit component and said first side of said support structure.14. The apparatus as defined in claim 4, where said support structure isa printed circuit board (PCB).